1. Field of the Invention
The present invention relates to a flat-type vibration motor, and more particularly, to a flat-type vibration motor capable of significantly reducing the generation of injection burrs during an injection molding process of an injection molding material.
2. Description of the Related Art
In general, various types of vibration generation devices have been mounted in portable electronic devices such as portable phones, game machines, portable information terminals, and the like, in order to prevent inconvenience to surrounding people due to audible sounds therefrom.
In addition, generally, since a flat-type vibration motor may sufficiently vibrate in a state in which miniaturization, lightness, and slimness are implemented, the flat-type vibration motor has been widely used as a means for notifying a user of call reception in a portable terminal.
Meanwhile, recently, a touch screen in which signals are simply input by touching characters or other icons displayed on a screen, a display device of the portable terminal, with a hand or a pen has been mainly used.
In addition, in order to allow a user to feel a touch sense at the time of touching a screen of the portable terminal, an apparatus for generating vibrations may be installed in the portable terminal.
As an apparatus for generating vibrations, various vibration motors are used as a vibration source, wherein the vibration motor may be divided into a flat-type vibration motor and a cylinder-type vibration motor according to a shape thereof and be divided into a brush-type vibration motor and a brushless-type vibration motor according to the presence and absence of a brush.
Among them, since a brush flat-type vibration motor may be manufactured to have a relatively small thickness, the brush flat-type vibration motor may be advantageous for miniaturization of a mobile phone, such that the brush flat-type vibration motor is now widely used.
Generally, in the flat-type vibration motor, a rotor having a coil and a weight body eccentrically disposed on a substrate rotates about a rotational shaft, to generate vibrations. In this case, the rotational shaft and the rotor are coupled to each other by a holder formed of a resin material on the substrate.
This holder may be coupled to the substrate through injection molding. However, in the flat-type vibration motor according to the related art, an injection molding material may be leaked to the outside of a mold during an injection molding process of forming this holder. The reason is that a gap is formed in a portion in which the substrate and the mold interlock with each other due to a circuit pattern formed on the substrate.
Since the injection molding material leaked to the outside of the mold through this gap may spread across the entire substrate, the leaked injection molding material is interposed between the substrate and the coil or the weight body, causing the coil or the weight body to be seated inaccurately.
Therefore, a structure of a flat-type vibration motor capable of suppressing leakage of an injection molding material has been required.